Added keyboard navigation for ListBox.

Need to override it for TreeView.

Perspex.Controls/Generators/ItemContainerGenerator.cs

@@ -33,7 +33,7 @@ namespace Perspex.Controls.Generators
                 return this.state;
             }
 
-            set
+            private set
             {
                 if (this.state != value)
                 {

Perspex.Controls/Primitives/SelectingItemsControl.cs

@@ -7,6 +7,7 @@
 namespace Perspex.Controls.Primitives
 {
     using System;
+    using System.Collections;
     using System.Linq;
     using Perspex.Controls.Presenters;
     using Perspex.Input;
@@ -19,6 +20,8 @@ namespace Perspex.Controls.Primitives
 
         static SelectingItemsControl()
         {
+            FocusableProperty.OverrideDefaultValue(typeof(SelectingItemsControl), true);
+
             SelectedItemProperty.Changed.Subscribe(x =>
             {
                 var control = x.Sender as SelectingItemsControl;
@@ -36,6 +39,81 @@ namespace Perspex.Controls.Primitives
             set { this.SetValue(SelectedItemProperty, value); }
         }
 
+        protected static int GetIndexOfItem(IEnumerable items, object item)
+        {
+            if (items != null)
+            {
+                int index = 0;
+
+                foreach (var i in items)
+                {
+                    if (object.ReferenceEquals(i, item))
+                    {
+                        return index;
+                    }
+
+                    ++index;
+                }
+            }
+
+            return -1;
+        }
+
+        protected int GetIndexOfItem(object item)
+        {
+            return GetIndexOfItem(this.Items, item);
+        }
+
+        protected virtual void MoveSelection(FocusNavigationDirection direction)
+        {
+            if (this.SelectedItem != null)
+            {
+                int offset = 0;
+
+                switch (direction)
+                {
+                    case FocusNavigationDirection.Up:
+                        offset = -1;
+                        break;
+                    case FocusNavigationDirection.Down:
+                        offset = 1;
+                        break;
+                }
+
+                if (offset != 0)
+                {
+                    var currentIndex = GetIndexOfItem(this.SelectedItem);
+                    var index = currentIndex + offset;
+
+                    if (index >= 0 && index < this.Items.Cast<object>().Count())
+                    {
+                        this.SelectedItem = this.Items.Cast<object>().ElementAt(index);
+                    }
+                }
+            }
+        }
+
+        protected override void OnKeyDown(KeyEventArgs e)
+        {
+            switch (e.Key)
+            {
+                case Key.Up:
+                    this.MoveSelection(FocusNavigationDirection.Up);
+                    break;
+                case Key.Down:
+                    this.MoveSelection(FocusNavigationDirection.Down);
+                    break;
+                case Key.Left:
+                    this.MoveSelection(FocusNavigationDirection.Left);
+                    break;
+                case Key.Right:
+                    this.MoveSelection(FocusNavigationDirection.Right);
+                    break;
+            }
+
+            e.Handled = true;
+        }
+
         protected override void OnPointerPressed(PointerEventArgs e)
         {
             IVisual source = (IVisual)e.Source;

Perspex.Input/FocusNavigationDirection.cs

@@ -0,0 +1,54 @@
+// -----------------------------------------------------------------------
+// <copyright file="FocusNavigationDirection.cs" company="Steven Kirk">
+// Copyright 2014 MIT Licence. See licence.md for more information.
+// </copyright>
+// -----------------------------------------------------------------------
+
+namespace Perspex.Input
+{
+    /// <summary>
+    /// Describes how focus should be moved.
+    /// </summary>
+    public enum FocusNavigationDirection
+    {
+        /// <summary>
+        /// Move the focus to the next control in the tab order.
+        /// </summary>
+        Next,
+
+        /// <summary>
+        /// Move the focus to the previous control in the tab order.
+        /// </summary>
+        Previous,
+
+        /// <summary>
+        /// Move the focus to the first control in the tab order.
+        /// </summary>
+        First,
+
+        /// <summary>
+        /// Move the focus to the last control in the tab order.
+        /// </summary>
+        Last,
+
+        /// <summary>
+        /// Move the focus to the left.
+        /// </summary>
+        Left,
+
+        /// <summary>
+        /// Move the focus to the right.
+        /// </summary>
+        Right,
+
+        /// <summary>
+        /// Move the focus up.
+        /// </summary>
+        Up,
+
+        /// <summary>
+        /// Move the focus down.
+        /// </summary>
+        Down,
+    }
+}

Perspex.Input/InputElement.cs

@@ -135,12 +135,12 @@ namespace Perspex.Input
 
         public void Focus()
         {
-            Locator.Current.GetService<IFocusManager>().Focus(this);
+            FocusManager.Instance.Focus(this);
         }
 
         protected virtual void OnGotFocus(RoutedEventArgs e)
         {
-            this.IsFocused = true;
+            this.IsFocused = e.OriginalSource == this;
         }
 
         protected virtual void OnLostFocus(RoutedEventArgs e)

Perspex.Input/Perspex.Input.csproj

@@ -54,6 +54,7 @@
   </ItemGroup>
   <ItemGroup>
     <Compile Include="FocusManager.cs" />
+    <Compile Include="FocusNavigationDirection.cs" />
     <Compile Include="ICloseable.cs" />
     <Compile Include="IFocusManager.cs" />
     <Compile Include="IFocusScope.cs" />